311 lines
11 KiB
C++
311 lines
11 KiB
C++
//===--- RecordLayout.h - Layout information for a struct/union -*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the RecordLayout interface.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_AST_RECORDLAYOUT_H
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#define LLVM_CLANG_AST_RECORDLAYOUT_H
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#include "clang/AST/CharUnits.h"
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#include "clang/AST/DeclCXX.h"
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#include "llvm/ADT/DenseMap.h"
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namespace clang {
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class ASTContext;
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class FieldDecl;
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class RecordDecl;
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class CXXRecordDecl;
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/// ASTRecordLayout -
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/// This class contains layout information for one RecordDecl,
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/// which is a struct/union/class. The decl represented must be a definition,
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/// not a forward declaration.
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/// This class is also used to contain layout information for one
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/// ObjCInterfaceDecl. FIXME - Find appropriate name.
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/// These objects are managed by ASTContext.
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class ASTRecordLayout {
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public:
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struct VBaseInfo {
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/// The offset to this virtual base in the complete-object layout
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/// of this class.
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CharUnits VBaseOffset;
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private:
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/// Whether this virtual base requires a vtordisp field in the
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/// Microsoft ABI. These fields are required for certain operations
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/// in constructors and destructors.
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bool HasVtorDisp;
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public:
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bool hasVtorDisp() const { return HasVtorDisp; }
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VBaseInfo() : HasVtorDisp(false) {}
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VBaseInfo(CharUnits VBaseOffset, bool hasVtorDisp) :
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VBaseOffset(VBaseOffset), HasVtorDisp(hasVtorDisp) {}
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};
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typedef llvm::DenseMap<const CXXRecordDecl *, VBaseInfo>
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VBaseOffsetsMapTy;
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private:
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/// Size - Size of record in characters.
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CharUnits Size;
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/// DataSize - Size of record in characters without tail padding.
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CharUnits DataSize;
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// Alignment - Alignment of record in characters.
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CharUnits Alignment;
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/// RequiredAlignment - The required alignment of the object. In the MS-ABI
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/// the __declspec(align()) trumps #pramga pack and must always be obeyed.
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CharUnits RequiredAlignment;
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/// FieldOffsets - Array of field offsets in bits.
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ASTVector<uint64_t> FieldOffsets;
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/// CXXRecordLayoutInfo - Contains C++ specific layout information.
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struct CXXRecordLayoutInfo {
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/// NonVirtualSize - The non-virtual size (in chars) of an object, which is
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/// the size of the object without virtual bases.
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CharUnits NonVirtualSize;
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/// NonVirtualAlignment - The non-virtual alignment (in chars) of an object,
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/// which is the alignment of the object without virtual bases.
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CharUnits NonVirtualAlignment;
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/// SizeOfLargestEmptySubobject - The size of the largest empty subobject
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/// (either a base or a member). Will be zero if the class doesn't contain
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/// any empty subobjects.
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CharUnits SizeOfLargestEmptySubobject;
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/// VBPtrOffset - Virtual base table offset (Microsoft-only).
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CharUnits VBPtrOffset;
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/// HasOwnVFPtr - Does this class provide a virtual function table
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/// (vtable in Itanium, vftbl in Microsoft) that is independent from
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/// its base classes?
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bool HasOwnVFPtr : 1;
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/// HasVFPtr - Does this class have a vftable that could be extended by
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/// a derived class. The class may have inherited this pointer from
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/// a primary base class.
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bool HasExtendableVFPtr : 1;
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/// EndsWithZeroSizedObject - True if this class contains a zero sized
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/// member or base or a base with a zero sized member or base.
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/// Only used for MS-ABI.
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bool EndsWithZeroSizedObject : 1;
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/// \brief True if this class is zero sized or first base is zero sized or
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/// has this property. Only used for MS-ABI.
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bool LeadsWithZeroSizedBase : 1;
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/// PrimaryBase - The primary base info for this record.
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llvm::PointerIntPair<const CXXRecordDecl *, 1, bool> PrimaryBase;
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/// BaseSharingVBPtr - The base we share vbptr with.
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const CXXRecordDecl *BaseSharingVBPtr;
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/// FIXME: This should really use a SmallPtrMap, once we have one in LLVM :)
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typedef llvm::DenseMap<const CXXRecordDecl *, CharUnits> BaseOffsetsMapTy;
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/// BaseOffsets - Contains a map from base classes to their offset.
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BaseOffsetsMapTy BaseOffsets;
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/// VBaseOffsets - Contains a map from vbase classes to their offset.
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VBaseOffsetsMapTy VBaseOffsets;
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};
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/// CXXInfo - If the record layout is for a C++ record, this will have
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/// C++ specific information about the record.
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CXXRecordLayoutInfo *CXXInfo;
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friend class ASTContext;
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ASTRecordLayout(const ASTContext &Ctx, CharUnits size, CharUnits alignment,
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CharUnits requiredAlignment, CharUnits datasize,
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ArrayRef<uint64_t> fieldoffsets);
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// Constructor for C++ records.
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typedef CXXRecordLayoutInfo::BaseOffsetsMapTy BaseOffsetsMapTy;
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ASTRecordLayout(const ASTContext &Ctx,
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CharUnits size, CharUnits alignment,
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CharUnits requiredAlignment,
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bool hasOwnVFPtr, bool hasExtendableVFPtr,
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CharUnits vbptroffset,
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CharUnits datasize,
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ArrayRef<uint64_t> fieldoffsets,
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CharUnits nonvirtualsize, CharUnits nonvirtualalignment,
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CharUnits SizeOfLargestEmptySubobject,
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const CXXRecordDecl *PrimaryBase,
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bool IsPrimaryBaseVirtual,
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const CXXRecordDecl *BaseSharingVBPtr,
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bool EndsWithZeroSizedObject,
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bool LeadsWithZeroSizedBase,
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const BaseOffsetsMapTy& BaseOffsets,
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const VBaseOffsetsMapTy& VBaseOffsets);
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~ASTRecordLayout() = default;
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void Destroy(ASTContext &Ctx);
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ASTRecordLayout(const ASTRecordLayout &) = delete;
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void operator=(const ASTRecordLayout &) = delete;
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public:
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/// getAlignment - Get the record alignment in characters.
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CharUnits getAlignment() const { return Alignment; }
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/// getSize - Get the record size in characters.
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CharUnits getSize() const { return Size; }
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/// getFieldCount - Get the number of fields in the layout.
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unsigned getFieldCount() const { return FieldOffsets.size(); }
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/// getFieldOffset - Get the offset of the given field index, in
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/// bits.
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uint64_t getFieldOffset(unsigned FieldNo) const {
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return FieldOffsets[FieldNo];
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}
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/// getDataSize() - Get the record data size, which is the record size
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/// without tail padding, in characters.
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CharUnits getDataSize() const {
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return DataSize;
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}
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/// getNonVirtualSize - Get the non-virtual size (in chars) of an object,
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/// which is the size of the object without virtual bases.
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CharUnits getNonVirtualSize() const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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return CXXInfo->NonVirtualSize;
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}
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/// getNonVirtualSize - Get the non-virtual alignment (in chars) of an object,
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/// which is the alignment of the object without virtual bases.
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CharUnits getNonVirtualAlignment() const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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return CXXInfo->NonVirtualAlignment;
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}
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/// getPrimaryBase - Get the primary base for this record.
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const CXXRecordDecl *getPrimaryBase() const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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return CXXInfo->PrimaryBase.getPointer();
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}
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/// isPrimaryBaseVirtual - Get whether the primary base for this record
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/// is virtual or not.
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bool isPrimaryBaseVirtual() const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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return CXXInfo->PrimaryBase.getInt();
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}
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/// getBaseClassOffset - Get the offset, in chars, for the given base class.
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CharUnits getBaseClassOffset(const CXXRecordDecl *Base) const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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assert(CXXInfo->BaseOffsets.count(Base) && "Did not find base!");
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return CXXInfo->BaseOffsets[Base];
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}
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/// getVBaseClassOffset - Get the offset, in chars, for the given base class.
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CharUnits getVBaseClassOffset(const CXXRecordDecl *VBase) const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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assert(CXXInfo->VBaseOffsets.count(VBase) && "Did not find base!");
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return CXXInfo->VBaseOffsets[VBase].VBaseOffset;
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}
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CharUnits getSizeOfLargestEmptySubobject() const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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return CXXInfo->SizeOfLargestEmptySubobject;
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}
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/// hasOwnVFPtr - Does this class provide its own virtual-function
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/// table pointer, rather than inheriting one from a primary base
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/// class? If so, it is at offset zero.
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///
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/// This implies that the ABI has no primary base class, meaning
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/// that it has no base classes that are suitable under the conditions
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/// of the ABI.
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bool hasOwnVFPtr() const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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return CXXInfo->HasOwnVFPtr;
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}
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/// hasVFPtr - Does this class have a virtual function table pointer
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/// that can be extended by a derived class? This is synonymous with
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/// this class having a VFPtr at offset zero.
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bool hasExtendableVFPtr() const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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return CXXInfo->HasExtendableVFPtr;
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}
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/// hasOwnVBPtr - Does this class provide its own virtual-base
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/// table pointer, rather than inheriting one from a primary base
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/// class?
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///
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/// This implies that the ABI has no primary base class, meaning
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/// that it has no base classes that are suitable under the conditions
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/// of the ABI.
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bool hasOwnVBPtr() const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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return hasVBPtr() && !CXXInfo->BaseSharingVBPtr;
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}
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/// hasVBPtr - Does this class have a virtual function table pointer.
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bool hasVBPtr() const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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return !CXXInfo->VBPtrOffset.isNegative();
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}
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CharUnits getRequiredAlignment() const {
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return RequiredAlignment;
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}
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bool endsWithZeroSizedObject() const {
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return CXXInfo && CXXInfo->EndsWithZeroSizedObject;
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}
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bool leadsWithZeroSizedBase() const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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return CXXInfo->LeadsWithZeroSizedBase;
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}
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/// getVBPtrOffset - Get the offset for virtual base table pointer.
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/// This is only meaningful with the Microsoft ABI.
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CharUnits getVBPtrOffset() const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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return CXXInfo->VBPtrOffset;
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}
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const CXXRecordDecl *getBaseSharingVBPtr() const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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return CXXInfo->BaseSharingVBPtr;
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}
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const VBaseOffsetsMapTy &getVBaseOffsetsMap() const {
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assert(CXXInfo && "Record layout does not have C++ specific info!");
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return CXXInfo->VBaseOffsets;
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}
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};
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} // end namespace clang
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#endif
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